William w



(No Model.)

W. W. BRSIGG.

BORING BIT.

No. 274,711. Patented Mar.27,1'88 3;-

INVENTOR WITNESSES: 7

ATTORNEY.

N PETERS. Photo-Lithograph". Walhington. [7.0

UNITED STATES PATENT OFFICE.

WILLIAM W. BBIGG, OF WASIZIINGrTON, DISTRICT OF COLUMBIA.

BORING-BIT.

SPECIFICATION forming part of Letters Patent No. 274,711., dated March27, 1883.

Application filed December 19, 1882. (N0 model.)

To all whom it may concern:

Be it known that I, WILLIAM W. BRIGG, a citizen of the United States ofAmerica,residingat Washington, in the District of Columbia, haveinvented certain newand useful Improvements in Boring-Bits, of which thefollowing is a specification, reference being had therein to theaccompanying drawings.

This invention relates to an improvement in boring-bits; and theinvention consists in the peculiar construction and arrangement ofparts, as hereinafter more particularly described and claimed.

In the accompanying drawings, Figures 1 and 2 represent side elevationsof my bit in difl'erent positions, Fig. 1 showing the flat side and Fig.2 the convex side; and Fig. 3 a cross-section on the line as :0.

A represents the bit, preferably made with two convex and two flatsides, each pair of sides being parallel. At the bottom is a screwpoint,a, preferably provided with a groove or cut extending down across thethread, the edges of which groove may be undercut or not, as preferred.

At B is shown a countersink, made with an oblong hole through it, havingtwo roundv sides and made to fit the boring-bit as shown. Thiscountersink has undercut cutting-edges, as shown at b in Fig. 3, whichare set at an angle of about forty-five degrees, as shown in Fig. l, anda slot, b, through which passes a spring, 0, fastened to the countersinkby a screw, D, or in any other convenient manner. The free end of thisspring catches into notches a in the flat sides of the bit, so that thecountersink may be adjusted at any desired point, according to the depthof hole desired. In lieu of the notches a, the spiral grooves on theconvex sides may be used by making the spring of such shape as to fitinto them instead of the notches.

By the use of the bit having flat parallel sides the countersink B willfit it at any point, whereas if the sides were made tapering theaperture in the countersink would be too large to fit the bit near thebottom, if

made large enough to fitit at the top. By my arrangement andconstruction I am enabled to combinethe benefit of a bit that bores ahole the full size forthe whole length, the flat cutting-edges to reamout the hole, and the use sides the countersink cannot turn, and henceis readily held in place by the spring-catch O. The screw-pointis also aconsiderable improvement on the flat bit, because, if made without itthereis little or 'no tendency to draw into the wood.

By making the countersink with the cutting-edge at or about the angleshown there is a tendency to draw the countersink into the wood, so thatbut little power is required to hold the countersink in place.

What I claim as new is-- 1. A boring-bit having its shank of the samesize in cross-section for its wholelength and provided with a Hat sideand a series of notches adapted to receive the spring-catch of acountersink, substantially as and for the purpose specified.

2. A boring-hit having two convex sides provided with spiral grooves andtwo flat sides,

each pair of sides being parallel, adapted to fit acorrespondingly-shaped recess in a countersink, whereby said countersinkwill accurately fit any portion of the bit, and thus prevent it from,turning thereon, substantially as described.

3. A boring-bit having a screw-point, two convex sides, provided withspiral grooves, and two flat sides, each pair of sides hein g parallel,substantially as described.

4. A boring-bit having a flat side, in combination with a countersinkhaving an aperture closely fitting all sides of. said bit to

